With development of an optoelectronic collection technology and an increasing requirement for a high-definition digital video, a video data volume becomes increasingly large. Limited heterogeneous transmission bandwidth and diversified video applications impose a higher requirement on video coding efficiency. In this case, the High Efficiency Video Coding (HEVC) standard starts to be formulated as required.
A basic principle of video coding compression is using correlation between a space domain, a time domain, and a codeword to eliminate redundancy as much as possible. At present, a common manner is using a block-based hybrid video coding framework to implement video coding compression by means of steps such as prediction (including intra-frame prediction and inter-frame prediction), transformation, quantization, and entropy coding. This coding framework is powerful, and the block-based hybrid video coding framework is also used for HEVC.
In various video encoding/decoding schemes, motion estimation/motion compensation is a key technology affecting encoding/decoding performance. In many existing video encoding/decoding schemes, it is generally assumed that a motion of an object meets a requirement of a translational motion model, and various parts of the entire object are in a same motion. An existing motion estimation/motion compensation algorithm is basically a block-based motion compensation algorithm based on a translational motion model (English: translational motion model). Existing inter-frame prediction is mainly block-based motion compensation (English: motion compensation) prediction based on a translational motion model. Some non-translational motion models (for example, an affine motion model) designed for non-translational motions gradually emerge.
In a prediction mechanism based on an affine motion model, low-precision motion vectors of two control points in a current picture block and the affine motion model may be used to perform pixel value prediction in the prior art, so as to obtain a low-precision predicted pixel value of the current picture block. During a process of the pixel value prediction, an interpolation filter needs to be used to perform an interpolation filtering operation. Precision of the obtained predicted pixel value of the current picture block is the same as precision of the motion vectors of the two control points. If a higher-precision predicted pixel value of the current picture block needs to be obtained, a bilinear interpolation filter is further required to perform secondary interpolation filtering on the obtained lower-precision predicted pixel value of the current picture block.
In the prior art, if the lower-precision motion vectors of the two control points and the affine motion model are used to obtain the higher-precision predicted pixel value of the current picture block, at least two interpolation filtering operations need to be performed (a relatively large quantity of intermediate caches and memory operations are required for each interpolation filtering operation). As a result, a relatively large quantity of intermediate caches and memory operations may be required during an entire picture prediction process, and calculation complexity becomes relatively high.